#1: There is the text of the law, and case law as how the text is interpret. "Within their knowledge" has to have some standard under case law. Did the McMasters actions fit both the text and interpretation of the law?
#2: I can't comment on this.
#3: There was probably cause: This is the big issue here. The McMichaels have said there were burglaries in the area, and claim to have seen video, except there were no reported burglaries for two months in the area and that video has not been presented. For now, we have only their word burglaries happened. Even if there were at some time in the past, that is not much reason to believe that seeing any specific person jogging or running or "hauling ass" down the street committed them.
I don't there was much reason to get guns here. Why not get a cellphone, follow, and call the police instead? Even if their actions were legal, they put themselves at risk of a wrongful death suit even if cleared of criminal charges. When it comes to civilians and lethal force, avoiding it is best. Civil suits are preponderance of evidence standard, and the the McMasters's actions make harder for them in a civil case.
#4: Good points.
#5: Good points.
#6: Arbery had legal rights too, people are forgetting that. If he was minding his own business and thought two people chasing him down in a truck wanted to put him in hospital or the morgue, and the driver pulled a shotgun as he was getting out of the truck, he had the right of self defense.
#7: "...I'm going to puke". On threads that get on my nerves I hear you.
It is not simply what Arbery thought; it is what a reasonable person in his position and with his knowledge at the time would have thought.
As has been noted in this thread, the McMichaels did not chase him down. We do not know what he thought, because he is dead.
An equally tenable theory, to a jury, could be that Arbery was running because he had Mens Rea, or guilty mind.
There are lots of guns in Georgia. Arbery might have seen the shotgun before he rounded the corner of the truck. It is not at all clear whether he did or not.
The law is not always clearly on one side or the other.
Both sides may have the law on their side. Both sides may have violated the law. Given the facts as presented, it appears to me the McMichaels did not violate the law.
Sometimes, things happen by misadventure.
It is not hard to construct a case for the jury that the McMichaels are not guilty.